David The objective of the project is to develop comparative theories of public policy from a political economy perspective; i.e., where the policy is chosen in a public institution embedded in a political system. The principal comparison will be between presidential and parliamentary systems with an emphasis on the influence of institutions and interests, the dynamics of the resulting policies, and their stability and efficiency. The political economy perspective takes into account the principal institutions of a political system and the representation of interests both within the political system through elections, for example, and through private actions such as lobbying and the provision of politically valuable resources to officeholders. The approach to be taken is to develop integrated political economy theories that incorporate political institutions and economic interests in a manner that allows for a comparison of policy choices both across political systems and across time. The research program has four principal components. The first is the development of a dynamic theory of parliamentary systems that includes institutions and interest groups. The second is the development of a corresponding theory of presidential systems that incorporates the presidential veto and Senate filibuster of the U.S. system. The third component is the development of a theory of endogenous political parties and their role in parliamentary and presidential systems. The fourth component is an integrated theory of market competition and political action at the industry level as a means of linking public policy to its effects on economic rents and linking those rents to the strategies of interest groups in attempting to influence the choice of policies. Finally, the objective is to compare the theories to identify the role of institutions and the organization of interest on public policy choices.